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M y o s i l i s ossilicaris - C l i i l d f i o o d

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Kiier

Schlüsselwörter M y o s i t i s ossificans

h~iyosilisossilic.nns circiiiiisc.ril)ia rc>l+rs l o Llir localis(d forrnation o f non-nroplastic 1ietr:rotopic bonr and cariilagc iii tlic? soli tissucs iii or sdjaccnt to musclc aiid i n piosiiiiity to bone. Most cases appear iii adiills aiicl are clearly rtblnLrd io a siriglr iiiqjor cpisodc oftraurna or repeated niinor traurna. I n a significarit graul) i,l'pntients thc proccss dcvclops w i t h no appclrcnt causc. and a rnalignant tiiniuur is orten siisprcted. Wa report ori sucli acase iii a child without history oftraurna.

Case report A 13-yenr-old boy prcscntrd w i t h pnin i n thc Icft knee for one rnonth and he denied any specific traiirna. X-ray shows a cortical dcfcct and an opacity of soft tissuc dcnsity abovc

iiiid postchi-iori o tli(s rric5dialcoiidyloof'thc fcniur. Onc month latcr a pairiful mass bcxcsiiicxpalpable iri thc lctt poplitcnl Iossa nnd ilic kiic.17 nmnsIicltl i n Il~.\;ioii. T1iei.c was aii alropliy of1.1i(! cliiildric:r~ps. X - r i ~ y s ,t\vo n ~ r r k sa f i r r t l i r first initial X-rays. i r v ~ a l e dcalcificatioiis at tlic prriphcry of tlic opacity (Fig. 1). A'")"'Tcclinctium scnn sliocvrd iiiai.krxi iiic.rtvisr iii t l i r u l ~ t a k t -iii Ilie Irsioii. Witli (:.I' (Fig. 2). t l i r r r \\'iis a r i n g o f ossificalion qiiitc distirict froin thc corI r x of t l i r fcmiiir blorcovcr. thcrc was somr pcriostal n c w bonc Iori~iatitnn.I ' h r (:'I' Iiiidiiigs \ w r P iiiIerprc?iti as r o i i s i 5 ~ ~ ~t.vi111 1i1 rnyositis ossific:itiis iintl no f i i r t h r r invrstigatiori scoinrd nrccssary. but bccausc of thc atrophy o f thc quadriccps. thc suigcori p c r Ii>riiiccl biopsy niid I'oiiiid ii